This invention relates to a nozzle and more particularly, to a multi-hole nozzle for a fuel injector which provides an improved level of atomization relative to prior pressure-driven atomization mechanisms or nozzles.
Nozzle assemblies are used in various devices such as automotive vehicles and are typically used to xe2x80x9catomizexe2x80x9d, vaporize or disperse pressurized liquid. For example and without limitation, one type of nozzle is typically and operatively disposed within a vehicle fuel injector and is used to atomize fuel before it is discharged into a combustion chamber of a vehicle engine. Particularly, the fuel injector nozzle is operatively and fixedly disposed within the fuel injector and is the last component or assembly that the fuel passes through before entering the combustion chamber.
The quality or level of atomization provided by the fuel injector nozzle directly and significantly effects the level of emissions and fuel economy of a vehicle. Particularly, a greater level or quality of atomization improves fuel economy and reduces emissions by promoting a more uniform and complete oxidation of hydrocarbons that are contained within the fuel. Furthermore, greater levels of fuel atomization provided by fuel injectors significantly reduce xe2x80x9ccold-startxe2x80x9d emissions and enable the usage of lower injection pressures for gasoline direct injection engines.
Various efforts have been made to increase the level of atomization provided by fuel injectors. For example and without limitation, nozzle assemblies with multiple holes have been used to increase the atomization of the fuel discharged from fuel injectors. However, these types of multi-hole nozzles do not always provide a significant improvement over single hole nozzles for practical hole sizes. Other efforts at increasing the level of fuel atomization provided by fuel injectors include providing an air delivery subsystem and increasing the pressure of the fuel by use of special pumps or additional components. These types of systems and methods, however, undesirably and significantly increase the cost of the fuel injection systems in which they are employed.
There is therefore a need for an improved fuel injector nozzle which overcomes some if not all of the drawbacks of prior fuel injector nozzles.
It is a first object of the invention to provide a nozzle which overcomes at least some of the previously delineated drawbacks of prior nozzles.
It is a second object of the invention to provide a nozzle which is adapted for use in combination with a vehicle fuel injector and which provides an improved level of atomization relative to prior fuel injector nozzles.
It is a third object of the invention to provide a nozzle for a fuel injector which provides an increased level of atomization of discharged fuel without substantially increasing the cost of the fuel injector.
According to a first aspect of the present invention, a nozzle is provided. The nozzle has a plurality of channels through which an amount of pressurized material selectively flows, and a plurality of chambers each of which is disposed at an end of a unique one of the plurality of channels and is effective to receive the pressurized material and to swirl the received pressurized material. Each of the plurality of chambers further includes an aperture which is effective to discharge the swirling pressurized material, thereby causing the discharged pressurized material to form a finely atomized spray.
According to a second aspect of the present invention, a method is provided for providing a nozzle for a fuel injector which discharges an amount of pressurized fuel. The method includes the steps of forming a plurality of channels within the nozzle, the plurality of channels being interconnected in a center portion of the nozzle and being effective to receive and channel the pressurized fuel; forming a plurality of chambers within the nozzle, each of the plurality of chambers being disposed at an end of a unique one of the plurality of channels which is remote from the center portion, the chambers being effective to receive the pressurized fuel and to cause the received pressurized fuel to spiral; and forming a hole within each of the plurality of chambers, the holes being effective to discharge the spiraling fuel as a finely atomized spray.
These and other features, aspects, and advantages of the invention will become apparent by reading the following specification and by reference to the following drawings.